Vintage Thing No.150 - Sprite motorcycles

The children's TV show Rentaghost had a Sprite in it, called Timothy Claypole, but he was nothing like this...

I am partial to Villiers two stroke 250s and so is my mate Colyn. When he mentioned he was restoring a Sprite, I initially thought he'd gone into bug-eyed British sportscars but then an ancient memory stirred of a thin-tubed trials iron and we were able to talk properly and not at cross purposes.

Simple but effective. I also like the lines of the GRP tank 

Sprite motorcycles are very rare. They have their origin in a special built by a plumber called Frank Hipkin who was a successful scrambler. His machine featured a duplex Cotton frame with an extra down tube running from headstock to engine mounting, effectively making it a triplex frame. With Norton front forks and an Alpha bottom end with a Greeves head and barrel, it proved a winning combination and requests for replicas soon followed.

The salient feature of this trials iron is the lightweight duplex frame.

Hipkin was a plumber by trade so knew about tubes. He went into partnership with another plumber called Fred Evans and they chose to use the best available components. To avoid Purchase Tax in the UK, Hipkin and Evans hit upon the idea of offering their bikes in unassembled kit form and, at £224 -10s-0d in 1964, a Sprite offered remarkable value for money. According to a cost calculator I found on the internet (so it must be true) that's about £4,000 in today's prices.

Production models featured a duplex frame and AMC forks, which were lighter. The split ends of these forks favoured the fitting of a Motoloy front hub. Fibreglass mudguards, tank, seat base and side panels completed the purposeful look and the side panels contained a car-type air filter unit and were shaped to easily display competition numbers.

Both scrambles and trials units were built with the trials versions having much more narrowly grouped front down tubes. They were offered in ready to run turnkey versions - I guess that would be kickstart style - or kit form to avoid purchase tax. In due course, customers could try before they bought by taking a demonstrator round a piece of rough ground next to the factory at Oldbury in Worcestershire.

By 1964, a scrambler frame for the Triumph 500 unit twin was also available and the Villiers 37A units were improved with Alpha bottom ends with modified Greeves barrels.

Colyn's machine dates from 1964 so is a very early example. The engine is a Villiers 37A bottom end without the full circle crank but with an alloy Parkinson barrel and head. It also uses a Parkinson piston although Colyn tells me that a standard Villiers item can be modified to suit. 

The Parkinson barrel and head are sought after performance equipment for Villiers engines

Colyn knows more about Villiers engines than most people will ever forget. He did a lot of trials riding in the sixties, which is where his interest began, and can still turn one of these babies round on a sixpence despite the passage of time and old injuries. What he likes most about Villiers 37A engines is the variety of machine to which they were fitted. You can pick and choose the best components in your build up as well. With square barrels and Alpha cranks, decent power can be wrung out of them, although still nothing like the later Spanish or Japanese two strokes.

On this Sprite he used an Amal 626 Concentric carburettor mounted on rubber.

Metal Profile forks grace the front end and the front and rear hubs are from a Tiger Cub. The front rim is a 21" while at the rear an 18" WM2 allows modern 400 x 18 tyres to be used.

Colyn made his own chain tensioner out of scraps and a small nylon block. He built the bike up over a number of years and his collection includes a Greeves, a Cotton and a DOT, all trials bikes, as well as a couple of Bantams, a Fantic and a 225cc Yamaha Serow. 

Subsequent Sprites were developed further starting with the introduction in 1965 of leading-link forks, using Girling dampers. Modifications to the headstock enabled the use of taper roller bearings and the option of AMC, BSA or Ceriani forks.

In 1966, the Monza version became available with the Villiers Starmaker engine for both trials and scrambling. The trails became progressively lighter and briefer, often lacking side panels and featuring just a token seat. Scramblers had a much better padded seat and the inner mudguard moulding featured a still-air chamber for the air filter and carb.

By 1967, a move away from Villiers units had begun and they went out of production in 1968, Fortunately, Sprites could accommodate Maico and Husqvarna engines by then. Remarkably, further development saw Sprite make copies of the Husqvarna units and it is said that some parts were directly interchangeable. These aluminium parts were cast in a small factory belonging in Tipton, which was latterly bought by Hipkin and renamed Sprite Alloy Castings. 

As Colyn pointed out to me, by 1968 Sprite was the sole all British trials machine on the market and, for 1970, the future looked rosy but after supplying an American agent with a major order, the importer went bankrupt. Hipkins and Evans managed to keep their business going but that escapade understandably ended motorcycle production.

In those simpler days when the Sprite was built, trade names didn't matter so much and Hipkin and Evans had no trouble from BMC over the use of the Sprite name.

I like the idea of them copying the Husky motors as well. Again, no lawyers lost any sleep over that. 

Much as I admire the early examples, with their ubiquitous Villiers engines, I think a Triumph 500 twin in a Sprite frame would make a brutally splendid device.